This publication provides a brief overview of the differentials in prevalence, risk factors and quality of life for persons with musculoskeletal disorders in Australia. Unless otherwise stated, this publication presents information sourced from the 2001 ABS National Health Survey (NHS). The publication also draws on data from the ABS Causes of Death collection, the 2003 ABS Survey of Disability, Ageing and Carers, and other ABS and non-ABS sources.

INQUIRIES

For further information about these and related statistics, contact the National Information and Referral Service on 1300 135 070.

MUSCULOSKELETAL CONDITIONS

Musculoskeletal conditions are defined as conditions of the bones, muscles and their attachments, and include joint problems such as arthritis. Although there are more than 100 musculoskeletal conditions the most common are osteoarthritis, rheumatoid arthritis, osteoporosis and back pain (AIHW 2004).

COMMON MUSCULOSKELETAL CONDITIONS

Osteoarthritis is a degenerative joint condition affecting the weight-bearing joints such as the hips, knees and ankles as well as the hands and spine. In the initial stages pain occurs in the joints during and after activity but as the condition progresses pain may be experienced from minimal movement or during rest (AIHW 2004).

Rheumatoid arthritis is an auto-immune disease causing chronic inflammation of the joints. It most commonly affects the hand joints and can lead to deformities of the hands (AIHW 2004).

Osteoporosis is a condition whereby there is a progressive loss of bone density and decrease in the strength of the skeleton with a resultant risk of fracture (AIHW 2002).

Chronic back pain can be attributed to numerous causes including muscle strain or the displacement of an intervertebral disc (AIHW 2004).

DATA SOURCES

In this publication, where data are referenced from the ABS National Health Survey (NHS), arthritis refers to osteoarthritis, rheumatoid arthritis and other forms of arthritis including type unknown. Back pain refers to back pain and problems, disc disorders and curvature of the spine that have lasted, or are expected to last, for six months or more. A person may have reported having more than one of these musculoskeletal conditions as a long-term condition.

Unless otherwise stated this article presents information sourced from the 2001 NHS. The information provided is as reported by the respondent, with no medical verification.

In view of the prevalence of arthritis and musculoskeletal conditions and their associated pain and disability, these conditions were identified as a National Health Priority Area in 2002. The conditions to be targeted initially are rheumatoid arthritis, osteoarthritis and osteoporosis (AIHW 2004).

PREVALENCE

In 2001, 32% (6 million) of the population reported having a disease of the musculoskeletal system and connective tissue as a long-term condition, where the condition lasted, or was expected to last, six months or more.

Fourteen percent of the population reported having arthritis, 1.6% of the population reported having osteoporosis and 21% of the population reported having back pain as a long-term condition.

PREVALENCE OF MUSCULOSKELETAL CONDITIONS BY AGE, 2001

DIFFERENTIALS IN PREVALENCE

AGE AND SEX

In 2001, the prevalence of arthritis for females (16%) was higher than that for males (11%).

The prevalence of back pain in 2001 was the same for both sexes (21%).

There was an increased prevalence of arthritis with age in 2001, with the condition reported by 43% of people in the 65-74 year age group and over half (52%) of people aged 75 and over.

The prevalence of osteoporosis also increased with age, particularly for females, with 10% of females in the 65-74 year age group and 15% of females aged 75 years and over, reporting the condition.

INDIGENOUS AUSTRALIANS

After adjusting for age differences footnote 1, Indigenous Australians reported having a disease of the musculoskeletal system and connective tissue at a similar rate to non-Indigenous Australians (35% and 32% respectively) (ABS 2001a).

Indigenous Australians were more than twice as likely to report having arthritis than non-Indigenous Australians (16% compared to 7%), after adjusting for age differences (ABS 2001a).

As with non-Indigenous Australians the rates of arthritis were higher in older Indigenous Australians, affecting 40% of those aged 55 years and over, similar to 41% of non-Indigenous Australians in the same age group (ABS 2001a).

SOCIOECONOMIC STATUS

In 2001, after adjusting for age and sex differencesfootnote 2, 20% of persons aged 15 years and over who lived in the most disadvantaged areas suffered from arthritis, in contrast to 15% of those who lived in the least disadvantaged areas (as measured as being in the first or fifth quintiles of the Index of Relative Socio-Economic Disadvantage (SEIFA) respectively).

The proportion of people aged 15 years and over who lived in the most disadvantaged areas and suffered from back pain (27%) was similar to the proportion of people who lived in the least disadvantaged areas and suffered from back pain (24%) (after data were adjusted for age and sex differences).

RISK FACTORS

Predisposing factors for rheumatoid arthritis and osteoarthritis are genetic factors (which may vary for each type), sex and age. The tendency to auto-immunity is also a risk factor for rheumatoid arthritis (AIHW 2002).

There are no well-established behavioural risk factors for rheumatoid arthritis (AIHW 2002).

Predisposing factors for osteoporosis include being female, family history of osteoporosis, low levels of oestrogen after menopause, amenorrhoea lasting more than 6 months before the age of 45 and early menopause (before age 45) (O'Neill 1997; Nuki et al. 1999).

Physical inactivity has been identified as a behavioural risk factor for osteoarthritis, but not for rheumatoid arthritis. Lack of physical exercise has also been identified as a risk factor for osteoporosis, particularly during growth and adolescence. However females who exercise excessively are also at risk due to oestrogen loss and mechanical stress on the skeleton (AIHW 2002). Gentle, regular exercise can improve an arthritic joint by nourishing the cartilage and easing stiffness (DHS 2004).

Persons aged 15 years and over with osteoarthritis (32%) in 2001 were as likely to be sedentary as those without osteoarthritis (31%) (after adjusting for age and sex differences).

In 2001, persons aged 15 years and over with and without osteoarthritis, and with and without osteoporosis, had a similar low level of exercise (38% for those with osteoarthritis, with osteporosis and without osteoporosis and 37% of those without osteoarthritis (after adjusting for age and sex differences)).

OVERWEIGHT AND OBESITY

Obesity has been identified as a behavioural risk factor for osteoarthritis, but not for rheumatoid arthritis (AIHW 2002).

People who are severely overweight are up to three times more likely to need total hip replacement surgery as a result of osteoarthritis compared with people of a healthy weight (myDr, 2001).

In 2001, approximately half the persons aged 15 years and over who had either osteoarthritis or back pain were overweight or obese, after adjusting for age and sex differences (50% and 47% respectively). This compares to 44% for the whole population aged 15 years and over.

QUALITY OF LIFE

In 2001 persons aged 18 years and over with rheumatoid arthritis, osteoarthritis or back pain were less positive about their quality of life than those without these conditions, after adjusting for age and sex differences. Of those with rheumatoid arthritis, 5.6% felt unhappy or terrible compared to 3.2% of those without the condition, of those with osteoarthritis, 4.5% felt unhappy or terrible compared to 3.1% of those without the condition, and of those with back pain, 4.5% felt unhappy or terrible compared with 2.8% of those without the condition.

After adjusting for age and sex differences, 32% of persons aged 18 years and over with rheumatoid arthritis reported being delighted or pleased with their life, compared to 43% of those without rheumatoid arthritis. Of those persons with osteoporosis, 33% gave a similar positive response compared to 43% without osteoporosis. A lower proportion of osteoarthritis sufferers were delighted or pleased with their life (38%) compared to 43% of those without osteoarthritis.

DAYS OUT OF ROLE

A person's role in life encompasses attendance at work, school or place of study, as well as activities that are usually undertaken. Suffering from a medical condition can impact on this role. In the fortnight preceding the time of interview for the 2001 NHS, 17% of the general population aged 15 years and over had been affected in some way in their role, after adjusting for age and sex differences. This compares to 28% of those suffering from rheumatoid arthritis, 24% of those suffering from osteoarthritis, 26% of osteoporosis sufferers and 24% of those suffering from back pain.

In the general population aged 15 years and over in 2001 who had their role affected in the previous two weeks, 4.2% reported having their role affected on each of the 14 days prior to the interview. This contrasts with those suffering from musculoskeletal conditions - 8.0% of those suffering from rheumatoid arthritis, 6.6% of those suffering from osteoarthritis, 8.2% of osteoporosis sufferers and 6.8% of those suffering from back pain had their role affected on all 14 days.

PREVALENCE OF PERSONS HAVING HAD A 'DAY OUT OF ROLE' IN THE PREVIOUS 14 DAYS (a)(b), 2001

DISABILITIES

The 2003 Survey of Disability, Ageing and Carers (SDAC) included people in both private and non-private dwellings, including people in cared accommodation establishments but excluding those in gaols and correctional institutions (ABS 2004a).

According to the SDAC, in 2003 musculoskeletal conditions accounted for more disability than any other medical condition, affecting 34% of people with a disability (ABS 2004a).

In 2003, 6.8% of the whole population had a disability related to diseases of the musculoskeletal system or connective tissue, more than any other medical condition (ABS 2004a).

Of those persons who reported a physical disability in 2003, 41% reported their main condition as a disease of the musculoskeletal system or connective tissue (ABS 2004a).

Nearly one third of those persons reporting a disease of the musculoskeletal system or connective tissue (28%) had either a profound or severe core activity restriction in mobility or self care (ABS 2004a).

HOSPITALISATIONS

Arthritis and other musculoskeletal conditions accounted for 18% of all hospital separations in 2001-02 (AIHW 2004).

HEALTH SYSTEM COSTS

In 2000-01, 9.5% of total allocated health expenditure ($4.7 billion) was spent on musculoskeletal conditions, only less than cardiovascular diseases (11.2%) and diseases of the nervous system (9.9%) (AIHW 2004).

The value of out-of-hospital medical services for musculoskeletal diseases is the highest of all the major disease areas (in broad disease group levels), with $879 million being spent on musculoskeletal diseases in the health sector in 2000-01 (AIHW 2004).

Hospital costs contributed 39% to the total health system costs on musculoskeletal conditions in 2000-01 (AIHW 2004b).

One quarter of total expenditure on musculoskeletal conditions was spent on treatments for osteoarthritis ($1.2 billion) in 2000-01, with nearly half of this (48%) being costs related to hospitals (AIHW 2004b).

Chronic back pain and slipped discs accounted for 19% of total health system costs for musculoskeletal conditions. People with these conditions accounted for 38% of all musculoskeletal expenditure on professional services such as physiotherapists, chiropractors and therapeutic massage therapists (AIHW 2004b).

HEALTH SYSTEM COSTS FOR MUSCULOSKELETAL CONDITIONS, 2000-01

MORTALITY

Arthritis and other musculoskeletal conditions account for a small percentage of death rates, but contribute more to disability rates (AIHW 2004).

In less than 1% of deaths registered in 2002, diseases of the musculoskeletal system were reported as the underlying cause of death and in a further 3% of deaths, diseases of the musculoskeletal system were reported as a contributing or associated cause of death (ABS 2002).

FOOTNOTES

1. Since many health characteristics are age-related, the age profile of the populations being compared needs to be considered when interpreting the data. To account for the differences in age structure, much of the comparative data contained within this publication are shown as age standardised percentages. For further detail, see the Explanatory Notes of the National Health Survey: Aboriginal and Torres Strait Islander Results, Australia, 2001, cat. no. 4715.0, ABS, Canberra. <Back

2. As some of the populations under study were small and the age and sex specific rates were unreliable, indirect age and sex standardisation was used with data from the NHS. <Back

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